Comparative effect of dense-and-disperse versus non-repetitive and non-sequential frequencies in electroacupuncture-induced analgesia in a rodent model of peripheral neuropathic pain

Background: Neuropathic pain (NP) is a complex disease that remains challenging to treat. Low-frequency dense-and-disperse (DD) electroacupuncture (EA) has been used as adjuvant therapy for neuropathic pain; however, its analgesic effect decreases as stimulation time increases, or when it is repeatedly used. We hypothesized that a new frequency parameter could improve the effectiveness of EA, and aimed to compare the efficacy and duration of the analgesic effect between classic DD-EA and non-repetitive and non-sequential frequency (random frequency (RF)-EA) in neuropathic rats. Furthermore, the effect of RF-EA at local traditional acupuncture point locations versus auricular vagus nerve stimulation (aVNS) was evaluated. Methods: Male Wistar rats with peripheral neuropathy were subjected to a single session of DD-EA or RF-EA for 20 or 40 min at ST36 + GB34. An additional group of rats was treated with RF-EA for 20 min using aVNS at the appropriate ear point locations. Paw pressure test, von Frey filaments and spontaneous pain scores were evaluated. Sham-operated rats were used as controls. Results: In all, 20 min of RF-EA reversed hyperalgesia (for 24 h) and allodynia (for 8 h), showing a longer analgesic effect than DD-EA. Both RF-EA and DD-EA induced partial inhibition of spontaneous pain for 8 h. Forty minutes of DD-EA did not interfere with the NP phenomena; however, RF-EA induced significant long-term analgesia. aVNS induced an analgesic effect similar to local stimulation. Conclusion: This pilot study shows that RF-EA at both local traditional acupuncture point and auriculotherapy point locations induces long-lasting analgesia in neuropathic rats, and more effectively so than classical DD-EA.

The role of noise in the early universe

In this paper, we consider a quantum mechanical system to model the effect of quantum fields on the evolution of the early universe. The system consists of an inverted oscillator bilinearly coupled to a set of harmonic oscillators. We point out that the role of noise may be crucial in the dynamics of the oscillator, which is analyzed using the theory of harmonic oscillators with random frequency. Using this analogy, we argue that due to the fluctuations around its mean value, a positive vacuum energy density would not produce an exponentially expanding but an oscillating universe, in the same fashion that an inverted pendulum is stabilized by random oscillations of the suspension point (stochastic Kapitza pendulum). The results emphasize the relevance of noise in the evolution of the scale factor.

BlueFMCW: Random Frequency Hopping Radar for Mitigation of Interference and Spoofing

Radars form a central piece in a variety of emerging applications requiring higher degrees of localization. However, two problems are anticipated as more radars are deployed: viz., (i) inter-radar interference and (ii) security attacks. While many prior proposals have addressed the problems, no work in the radar literature addressed them simultaneously. In this context, we introduce a novel frequency-modulated continuous-wave (FMCW) radar scheme (namely, BlueFMCW) that aims to alleviate the damage from interference and active attacks (e.g., spoofing). The technique designs that the waveform randomly hops across multiple frequencies to dilute the damage at a certain frequency. Moreover, we propose a phase alignment algorithm to remove the phase discontinuity while combining the beat signals from the randomly-hopped chirps. The simulation results show that the proposed technique can efficiently mitigate the interference and spoofing signals in various scenarios without costing its resolution.

Effects of mechanical vibration on designed steel-based plate geometries: behavioral estimation subjected to applied material classes using finite-element method

A research subject in structural engineering is the problem of vibration under a loading object. The two-dimensional (2D) model of a structure under loading is an example. In general, this case uses an object that is given a random frequency, which then causes various changes in shape depending on the frequency model. To determine the difference in performance by looking at the different forms of each mode, modal analysis with ANSYS was used. The samples to be simulated were metal plates with three variations of the model, namely, a virgin metal plate without any holes or stiffness, plates with given holes, and metal plates with stiffness on one side. The model was simulated with modal analysis, so that 20 natural frequencies were recorded. The sample also used different materials: low-carbon steel materials (AISI 304), marine materials (AISI 1090), and ice-class materials (AR 235). Several random-frequency models proved the deformation of different objects. Variations of sheet-metal designs were applied, such as pure sheet metal, giving holes to the sides, and stiffening the simulated metal sheet.